Trays are used in the micro-electronic industry for storing, transporting, fabricating, and generally holding small components such as, but not limited to, semi-conductor chips, ferrite heads, magnetic resonant read heads, thin film heads, bare dies, bump dies, substrates, optical devices, laser diodes, preforms, and miscellaneous mechanical articles such as springs and lenses.
Semi-conductor chips (chips) are illustrative of the issues associated with handling the above-defined components. Semi-conductor chips are very small electronic devices which, for purposes of economy and scale, are manufactured en-masse from a larger semi-conductor wafer (wafer). Typically, a single wafer will yield several tens or hundreds of chips. Often, after the wafer has been segmented into individual chips, additional processing is necessary. This usually entails transporting a plurality of chips from one workstation to another for processing by specialized equipment.
To facilitate processing of chips on a large scale, specialized carriers called matrix trays (trays) have been developed. These trays are designed to hold a plurality of chips in individual processing cells or pockets arranged in a matrix or grid. The size of the matrix or grid can range from two to several hundred, depending upon the size of the chips to be processed. Examples of specialized chip carriers are disclosed in U.S. Pat. Nos. 6,079,565 and 5,791,486 assigned to the owner of the present invention, and which are hereby fully incorporated herein by reference.
Electronic device fabrication processes, particularly where semiconductors are involved, are often extremely sensitive to contamination. Contamination and contaminants can be generated in many different ways. For example, particulates can be generated mechanically by wafers as they are processed, or they can be generated chemically in reaction to different processing fluids. Contamination can also be the result of out-gassing from chemical fabrication processes, or biological in nature due to human activity.
As a tray carrier is used through a fabrication process, it will generally accumulate some amount of contamination. After use, the carrier may be discarded or recycled, or the contamination may be cleaned off and the carrier reused. In the past, cleaning of tray carriers has often been considered uneconomical in view of the relatively low cost of new tray carriers and the relatively high cost and difficulty of cleaning and reusing contaminated tray carriers.
Previously, cleaning of tray carriers has been made more difficult and expensive due to the need to dry the tray after cleaning with water or other solvents. The tray carrier may have intricate arrangements of surfaces that are difficult to dry. In addition, a residual amount of the cleaning fluid may adhere to the surfaces of a carrier as a film or in a multiplicity of small droplets after the washing step. Any contaminants suspended in the residual cleaning fluid may be redeposited on the surface as the fluid dries, leading to contaminant carryover when the carrier is reused. Consequently, process efficiency and effectiveness is diminished overall. Reuse of tray carriers is discouraged, leading to environmentally undesirable proliferation of solid waste.
What is still needed in the industry is a tray carrier with features that promote more effective cleaning and drying of the carrier with reduced levels of residual process contamination.